U.S. patent application number 10/109140 was filed with the patent office on 2003-10-02 for one trip through tubing window milling apparatus and method.
Invention is credited to Pitman, Malcolm D., Toulouse, Jeffrey E..
Application Number | 20030183388 10/109140 |
Document ID | / |
Family ID | 28453026 |
Filed Date | 2003-10-02 |
United States Patent
Application |
20030183388 |
Kind Code |
A1 |
Toulouse, Jeffrey E. ; et
al. |
October 2, 2003 |
One trip through tubing window milling apparatus and method
Abstract
A one-trip through tubing window milling system is disclosed.
The whipstock is delivered with the mill and downhole motor in a
downhole assembly which further includes MWD equipment for proper
whipstock orientation. The entire assembly is run through tubing
and the MWD equipment orients the whipstock. A motor lock prevents
the downhole motor from turning as fluid pressure is applied to
properly anchor the whipstock below the production tubing. The
motor lock is defeated and the milling commenced using the downhole
motor. At the conclusion of the window milling, the bottom hole
assembly, including the mill, is removed and a retrieving tool
releases the whipstock for retrieval through the production
tubing.
Inventors: |
Toulouse, Jeffrey E.;
(Aberdeen, GB) ; Pitman, Malcolm D.; (Aberdeen,
GB) |
Correspondence
Address: |
Richard T. Redano
Duane Morris LLP
Suite 500
One Greenway Plaza
Houston
TX
77046
US
|
Family ID: |
28453026 |
Appl. No.: |
10/109140 |
Filed: |
March 28, 2002 |
Current U.S.
Class: |
166/298 ;
166/117.6; 166/55.1 |
Current CPC
Class: |
E21B 23/04 20130101;
E21B 7/061 20130101; E21B 29/06 20130101; E21B 4/02 20130101 |
Class at
Publication: |
166/298 ;
166/55.1; 166/117.6 |
International
Class: |
E21B 029/06; E21B
023/12; E21B 043/11 |
Claims
We claim:
1. A method of window milling comprising: connecting a mill to a
whipstock; running said mill and whipstock together through well
tubing and out of the lower end of said well tubing; anchoring the
whipstock in a larger tubular below said well tubing; milling the
window.
2. The method of claim 1, further comprising: orienting the
whipstock prior to said anchoring.
3. The method of claim 2, further comprising: connecting a downhole
motor to said mill before running said mill and whipstock through
well tubing.
4. The method of claim 3, further comprising: using a fluid driven
motor as said downhole motor; releasably locking a rotor on said
fluid driven motor.
5. The method of claim 4, further comprising: using fluid pressure
to accomplish said anchoring.
6. The method of claim 5, further comprising: removing said mill
through said tubing; inserting a retrieving tool through said well
tubing; removing said whipstock through said well tubing.
7. The method of claim 6, further comprising: using a linkage
connecting said whipstock and a gripping member as an anchor for
said whipstock; actuating said linkage to an anchoring position
with said fluid pressure.
8. The method of claim 7 further comprising: using said retrieving
tool to relieve fluid pressure; relaxing said linkage due to said
fluid pressure relieving.
9. The method of claim 4, further comprising: using mechanical,
fluid pressure or electrical power to unlock said rotor for
rotation.
10. The method of claim 4, further comprising: using a shiftable
spline to selectively engage a spline on said rotor for said
locking; separating said splines; locking said splines in a
separated position.
11. The method of claim 7, further comprising: providing a piston
in a housing; connecting an actuator rod to said piston near one
end and to said linkage near the other end; applying fluid pressure
to move said piston and said actuator rod to expand said
linkage.
12. The method of claim 11, further comprising: retaining pressure
on said piston in a chamber of said housing; providing a bias on
said piston to oppose said retained pressure in said housing; using
said retrieving tool to release said pressure from said
chamber.
13. The method of claim 12, further comprising: providing a valve
on said chamber and an operator for said valve extending into a
retrieving slot in said whipstock; moving said operator with said
retrieving tool; allowing said piston to be biased as a result of
said pressure releasing.
14. An anchor system for a through well tubing whipstock
comprising: a whipstock; a gripping member connected to said
whipstock and selectively pivotally moveable between a retracted
position, allowing said whipstock to be advanced through tubing and
a gripping position where the whipstock is anchored below the
tubing through which it was delivered; a fluid powered actuator for
selective pivoting of said gripping member into said gripping
position below said well tubing.
15. The system of claim 14, comprising: a linkage connecting said
gripping member to said whipstock; said fluid powered actuator
comprising a fluid powered piston connecting to said linkage with a
rod.
16. The system of claim 15, wherein: said piston defines a pressure
chamber in a housing for actuation of said rod in a first direction
when said chamber is pressurized; said rod sealingly extends
through said housing; said pressure chamber comprising a valve
which can be opened for relief of pressure in said chamber.
17. The system of claim 16, wherein: said piston is subject to a
bias in a direction opposite the said first direction; said
whipstock comprising an opening for engagement by a retrieving
tool; said valve operable through said opening to relieve pressure
in said chamber so that said bias can move said piston and in turn
said linkage toward said retracted position.
18. A lock for a downhole fluid driven motor comprising: a motor
housing; a rotor mounted in said motor housing; a releasable lock
preventing rotation of said rotor, said lock releasable after said
motor housing is delivered downhole.
19. The lock of claim 18, wherein: said releasable lock can be
defeated by at least one of an applied physical force, fluid force,
or electric power.
20. The lock of claim 19, wherein: said motor housing comprises a
stator, said rotor rotatably mounted to said stator and driven by
fluid flow through said stator; said rotor comprising at least one
projection which is engaged by a moveable member releasably
supported by said stator; said moveable member, responsive to
applied fluid force moves to an unlocked position where said
projection on said rotor is disengaged.
21. The lock of claim 20 wherein: said moveable member becomes
locked in said unlocked position.
22. The lock of claim 19, wherein: said rotor is releasably
connected to said stator by a breakable member, whereupon flow
through said stator sufficient torque is developed to break said
breakable member.
23. The lock of claim 22, wherein said breakable member is sheared
by torque developed by said rotor.
Description
FIELD OF THE INVENTION
[0001] The field of this invention relates to window milling
systems which can be accomplished through the production tubing in
a single trip.
BACKGROUND OF THE INVENTION
[0002] Many times in the history of producing wells, a lateral
opening must be milled in the casing in order to continue
production from an existing well. In the past it has been
advantageous to be able to set a whipstock and mill a window
without removing the production tubing. These techniques involve
the use of a retrievable whipstock which is insertable through
tubing. A good example of a through tubing retrievable whipstock is
U.S. Pat. No. 5,909,770. In some instances in the past, a through
tubing non-retrievable whipstock has been used in a multiple trip
system for milling a window in a casing. In U.S. Pat. No. Re 36,526
a through tubing non-retrievable whipstock is delivered through
tubing and anchored in the casing. A separate trip is involved in
delivering the mill or mills to mill the window in the casing.
[0003] In the past, whipstocks have been oriented downhole using
measurement while drilling technology known as MWD. MWD tools
required high flow rates for operation in orienting the whipstock
appropriately. In the past, mills have been driven by downhole
motors, generally of the progressing cavity type, involving a fixed
stator and a rotating rotor driven by fluid flow through the
stator.
[0004] One of the impediments in the past to running one-trip
through tubing systems for milling windows, has been that use of
applied pressure to set a whipstock anchor if delivered through the
downhole motor would start the motor turning, which would
prematurely break the mill loose from the whipstock prior to proper
setting of the whipstock or it would alternatively rotate the
whipstock. Accordingly, in developing the one-trip through tubing
window milling system of the present invention, a motor lock has
been developed for the downhole motor to prevent movement of the
rotor as the anchor for the whipstock is being set. The apparatus
and method of the present invention also envision hydraulically
setting an anchor for the through tubing whipstock while having a
way to retrieve the whipstock after the window is milled. The
hydraulic anchoring assembly is preferred, particularly in deviated
well applications due to the difficulties in properly actuating
mechanically any anchor for the whipstock. The retrieval of the
whipstock after the window milling necessarily involves release of
the whipstock anchor to facilitate the removal of the whipstock
through tubing. Accordingly, the present invention truly discloses
a one-trip through tubing system for window milling whose details
will be apparent to those of ordinary skill in the art from reading
the detailed description of the preferred embodiment which appears
below.
SUMMARY OF THE INVENTION
[0005] A one-trip through tubing window milling system is
disclosed. The whipstock is delivered with the mill and downhole
motor in a downhole assembly which further includes MWD equipment
for proper whipstock orientation. The entire assembly is run
through tubing and the MWD equipment orients the whipstock. A motor
lock prevents the downhole motor from turning as fluid pressure is
applied to properly anchor the whipstock below the production
tubing. The motor lock is defeated and the milling commenced using
the downhole motor. At the conclusion of the window milling, the
bottom hole assembly, including the mill, is removed and a
retrieving tool releases the whipstock for retrieval through the
production tubing.
DETAILED DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a schematic of the bottom hole assembly for the
apparatus and method of the present invention.
[0007] FIG. 2 is a sectional view showing the motor lock in the
engaged position. FIG. 2a is the view of FIG. 2 in the unlocked
position.
[0008] FIG. 3 is a sectional view of the whipstock anchoring
system, including a detail of the piston actuator;
[0009] FIG. 4 is a sectional view showing the whipstock anchored in
place prior to milling.
[0010] FIG. 5 is a sectional view showing the onset of milling;
[0011] FIG. 6 shows the insertion of the retrieval tool for removal
of the whipstock after the window has been milled;
[0012] FIG. 7 is the view of FIG. 6 with the whipstock anchor
defeated prior to removal of the whipstock through the production
tubing; and
[0013] FIGS. 8 and 9 are alternative locks to the preferred design
shown in FIGS. 2 and 2a.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0014] Referring to FIG. 1, the apparatus A may be delivered on
coiled tubing 10 or in the alternative, rigid tubing. Connected to
the lower end of coiled tubing 10 is a motor head assembly 12. The
motor head assembly is a tool that combines several tools to reduce
overall length, such as a connector and flapper valves. Below the
motor head assembly 12 is an MWD tool 14. In the preferred
embodiment, the motor head assembly 12 can be one that is provided
by Baker Oil Tools under Product Family No. H13203. The MWD tool 14
is of a type known in the art which uses mud pulse telemetry to
relay back to the surface downhole parameters of inclination
orientation as well as other properties. The MWD equipment can be
omitted if the direction of the lateral is not important.
[0015] Located below the MWD tool 14 is an orienting tool 16, one
example of which is Baker Oil Tools Product No. 132-61. The
orienting tool 16 offers the ability to orient a milling assembly
during a through tubing operation. This tool is actuated using back
pressure created by pumping through the retrieving tools or
workover motor which can be mounted below. In operation, the
internal pressure causes a piston in this tool to shift causing the
housing to rotate. When the pressure is reduced, the tool resets to
allow the next orientation cycle. This tool has the capability of
being prevented from free rotation in either direction.
[0016] Located below the orienting tool 16 is a whipstock valve 18.
One example of a whipstock valve 18 is Baker Oil Tools Product
Family H15036. This type of equipment allows operation of MWD
equipment in conjunction with a milling system to allow a one trip
operation. In this particular application, it allows the MWD tool
14 to operate to orient a whipstock as will be explained below.
This valve is actuated by hydraulic signals such as varying the
flow rate. This valve is normally open to facilitate the operation
of the MWD tool 14 and after the flow rate is raised considerably,
the bypass valve 20 will close to permit setting of the whipstock
anchor as will be described below.
[0017] Below the whipstock valve 18 is the mud motor 22. This is a
progressing cavity type motor in the preferred embodiment, one
example of which is the line of work over motors available form the
Inteq Division of Baker Hughes.
[0018] Located below the mud motor 22 is the lock 24 shown in more
detail in FIG. 2. Below lock 24 is the milling system 26 which is
in turn connected to the whipstock 28. The details of the whipstock
28 are shown in FIG. 3.
[0019] The entire assembly of FIG. 1 is made so that it will fit
through the production tubing 30 which is in turn inside the casing
32 as illustrated schematically in FIG. 4.
[0020] The operation of the lock 24 is best understood by looking
at FIG. 2. The mud motor 22 has a stator 34 inside of which is a
rotor 36. A thread 38 at the lower end of the rotor 36 is used to
engage the splined extension 40. The splined extension 40 is simply
a round shaft having a series of longitudinal splines 42 at a lower
end 44.
[0021] Secured to the stator 34 is a bottom sub 44 which is
attached at thread 46. Top sub 48 is releasably secured to the
bottom sub 44 with a shear pin or pins 50. Top sub 48 also includes
an o-ring seal 52 to provide a seal between itself and the bottom
sub 44. Further, the top sub 48 includes a circular groove 54. The
bottom sub 44 has a split c-ring 56. In the run in position shown
in FIG. 2, the c-ring 56 is held to the bottom sub 44. Ultimately,
as shown in FIG. 2a, when there is relative movement between the
bottom sub 44 and the top sub 48, groove 54 comes into alignment
with c-ring 56 to lock the relative positions between the bottom
sub 44 and top sub 48 in a manner where the splines 42 are no
longer retained by splines 58 on the top sub 48. This occurs
because of pressure build up which breaks the shear pin 50 and
longitudinally shifts the top sub 48 taking with it the splines 58.
Splines 58 move downwardly sufficiently so that when the c-ring 56
expands into groove 54, the rotor 36 is free to rotate. Once the
lock 24 shown in FIG. 2 is shifted to its unlocked position with
c-ring 56 and groove 54, it cannot return to the original position
shown in FIG. 2. In the run in position shown in FIG. 2, a torque
pin 60 prevents relative rotation between the top sub 48 and the
bottom sub 44 for transmission of rotational inputs to the
whipstock 28 for its proper positioning. The presence of the torque
pin 60 does not preclude the longitudinal shifting of the top sub
48 which is necessary to unlock the rotor 36 in the manner
previously described. Alternative locks are shown in FIGS. 8 and 9.
FIG. 8 shows an offset boss to lock the rotor 36 to the stator 34.
FIG. 9 shows a shearable key on the bottom of the bearing housing
extending into the upset of the drive sub.
[0022] Referring now to FIG. 3, the anchoring procedure for the
whipstock 28 will be described. The milling system 26 has a hose 62
connected to a piston 64. Piston 64 is biased by spring 66. Piston
64 is mounted in housing 68 and has seals 70 and 72. Seal 70 and 72
define an enclosed chamber 74 which has variable volume on piston
movement. Extending through chamber 74 is a drive rod 76 which
extends to a linkage 78 shown in FIG. 3 in the run-in position. A
shear valve 80 is connected to a shear rod 82. Shear rod 82 extends
into retrieving slot 84. The shear rod 82 is engagable in
retrieving slot 84 by a retrieving tool 86 as shown in FIG. 6. The
piston 64 has a check valve 88 which allows flow from hose 62 to
enter chamber 74 and increase its volume while at the same time
compressing spring 66 as the piston 64 moves upwardly. Upward
movement of the piston 64 takes with it the drive rod 76 which in
turn puts an upward pull on the linkage 78. This in turn drives the
gripping bar 90 into the casing 32 wedging the whipstock 28 against
the casing 32 as shown in FIG. 4. The retrieving tool 86 ultimately
moves the shear rod 82 which breaks the shear valve 80 which vents
accumulated pressure in chamber 74 thus allowing spring 66 to bias
the piston 64 to the right making chamber 74 have a smaller volume
as fluid is expelled from the broken shear valve 80. An upward pull
on the retrieving tool 86 brings out the whipstock 28 after the
window has been milled as will be described below.
[0023] The assembly shown in FIG. 1 is run through the tubing 30 to
get the whipstock 28 in the desired depth. Circulation is
established through the MWD tool 14 which exits through the
whipstock valve 18. When the proper orientation has been achieved,
the flow is increased to close the bypass valve 20 on the whipstock
valve 18. This allows for pressure buildup in hose 62 which in turn
forces piston 64 against spring 66. The final position of the
piston 64 is held by the presence of the check valve 88. Upward
movement of the piston 64 pulls up the drive rod 76 which in turn
actuates the linkage 78 to wedge the gripper bar 90 against the
casing 32. At this time the whipstock 28 is secured in the proper
orientation. The same pressure buildup in hose 62 also acts to put
a downward force on top sub 48 ultimately breaking the shear pin or
pins 50 and allowing the top sub 48 to shift until the c-ring 56
expands into the groove 54 locking the lock 24 in the unlocked
position. This in turn allows the rotor 36 to rotate as the splines
42 on spline extension 40 are no longer engaged to the splines 58
on the top sub 48. The milling operation can now take place as
illustrated in FIG. 5. At the conclusion of the milling operation,
the assembly shown in FIG. 1, except for the now anchored whipstock
28, is removed from the wellbore through the tubing 32. Inserted
through the tubing 32 is a retrieving tool 86, which extends into
the retrieving slot 84 as shown in FIG. 6. An upward pull on the
retrieving tool 86 when in retrieving slot 84, results in up hole
actuation of the shear rod 82 which breaks the shear valve 80. This
in turn allows the fluid in chamber 74 to escape. This in turn
allows the spring 66 to bias the piston 64 in the downhole
direction which in turn acts to collapse the linkage 78. An upward
pull on the retrieving tool 86 fully collapses the linkage to allow
retrieval of the whipstock 28 through the tubing 30.
[0024] Those skilled in art can appreciate that the preferred
embodiment has been revealed and that there are other techniques
available to accomplish the desired goals of the present invention.
The lock 24 can be released by a pickup force to break the shear
pin 50. Alternatively, as previously described, hydraulic pressure
can be used. Yet another alternative could involve using electrical
current to be applied to a solenoid to place the lock 24 in the
released position where the rotor 36 can rotate. The assembly
revealed in FIG. 1 allows a whipstock 28 to be run, oriented and
set when run below a motor and milling assembly on coil tubing or
drill pipe. A one trip system for through tubing window milling is
now made possible. Downhole motors in combination with coil tubing
allow the window to be milled through tubing when rotating the
drill string is not feasible. The lock 24 prevents free rotation of
the mud motor 22 which is necessary when coil tubing is used as the
work string to prevent running of the milling assembly when the
whipstock is set. Without the lock 24, the whipstock would rotate
on application of fluid through the motor 22. The lock 24 can be
built into the downhole motor 22 or can be a separate assembly.
[0025] While the preferred embodiment has been set forth above,
those skilled in art will appreciate that the scope of the
invention is significantly broader and as outlined in the claims
which appear below.
* * * * *